In recent years, thickness of a portable communication terminal has been reduced and whereby convenience of carrying the device has been greatly improved. On the other hand, especially, it becomes difficult for a user to perform an opening operation of the folding portable terminal with one hand. Therefore, various technologies which make the opening operation of the folding portable terminal easy are offered.
For example, in a portable device disclosed in Japanese Patent Application Laid-Open No. 2008-85865 (refer to FIG. 5 to FIG. 10 and paragraphs 0084 to 0105), in a closed state that a first case is folded over a second case, a protruding portion used for hooking a finger is formed by fluctuating one of the cases around a pivot shaft. And with that the opening operation is made easy.